In LTE systems, the base station dynamically allocates dedicated uplink resources to user terminals operating within the wireless network. The basic assumption is that uplink resources are allocated only when the user terminal has data to send. When the user terminal has data to send, it sends a Scheduling Request (SR) to the base station at the first opportunity to request resources for the uplink transmission and waits for a Scheduling Grant (SG). The base station dynamically allocates dedicated uplink resources to the requesting user terminal and sends an uplink Scheduling Grant (SG) to the user terminal identifying the allocated uplink resources. Buffer Status Reports (BSRs) are transmitted from the user terminals to the base station to provide information about buffer levels of the user terminal and to assist in the allocation of uplink resources.
The dynamic allocation of uplink resources can significantly increase the transmission efficiency so that uplink resources are not left unused if some of the user terminals have no data or only a small amount of data to send. In some scenarios, however, dedicated resource scheduling takes too long. For example, the user plane latency for scheduling uplink transmission on dedicated uplink resources is in the order of 11.5 ms due to uplink control channel cycle times, transmission times, and processing delays associated with the generation, transmission, and decoding of the SR and SG. The 3GPP LTE-Advanced target for user plane latency is 10 ms or less. Thus, there remains a need for improved resource scheduling processes to reduce the time required to access uplink resources.